"This is simply wrong as a matter of human biology and if you can't see that, there really isn't much to talk about," the letter stated. "Chloie was born, genetically — as a matter of fact — with an X and a Y chromosome and all of the anatomy of a male of the human race. Today, notwithstanding any hormone therapy or surgeries, Chloie still has an X and Y chromosome. Thus, you're statement is categorically, empirically, false."

The letter added that Chloie was not restricted from the competition: She just had to compete in the male division.

"I also understand that in your client-centric world, your concern is entirely for what your client wants, however, we have an obligation to protect the 'rights' of all competitors and the competition itself," the letter said. "We are scrupulous about ensuring a level playing field for the athletes."

The problem is that CrossFit doesn't really know what it's talking about.

Science has also shown that people who transition do not retain the athletic benefits from the original gender. A study in the Journal of Clinical Endocrinology and Metabolism showed that 20 male-to-female subjects who were taking testosterone-suppression treatments ended up gaining fat in feminine-heavy areas, like the hips, thighs and the buttocks.

Other research published in the European Society of Endocrinology found that male-to-female transsexuals had a significant decrease of thigh muscle within one year of starting hormone treatments. The authors noted, however, that these people did still have more muscle than female-born subjects three years after starting treatment.

Still, a 2005 review in the British Journal of Sports Medicine argued that there is no evidence that a preponderance of muscle equals a superior talent for sports. And while a person's height can't be changed, it isn't the only factor that makes him or her a superior athlete. The author concluded that there was not enough evidence to show whether or not male-to-female transsexuals would have an athletic advantage.

After reviewing the evidence, the International Olympic Committee in 2004 allowed transgender athletes to compete in the gender they transitioned to. The athletes are required to complete surgical reassignment surgery and undergo at least two years of hormone therapy (testosterone for female-to-male individuals and testosterone suppression for male-to-female individuals) to qualify.

In 2011, the NCAA allowed transgender athletes to compete on the collegiate level — even if they haven't had the surgical procedures.

The NCAA in its "Transgender Handbook" debunked the notions that people born male would have advantages over females, and that men would pretend to be trans females in order to have a competitive advantage.

The organization pointed out that the decision to change genders was not taken lightly by any individual. In the NCAA's 40-year history of requiring "sex verification" procedures, there has been no proof that any man has pretended to be a woman.

But perhaps more importantly, the NCAA also noted that transgender girls who transition before going through puberty do not get the male characteristics. And even if the person chooses to transition to a woman after puberty, she likely will fall within the natural diversity of body types that is seen among female-born women. Just because a person is a trans woman doesn't mean she'll automatically be tall or uniquely well-built for her sport.

According to the Advocate, Jonnson is only 5'4". This means that there is a good chance that many female-born women in the competition will be taller and larger than her.

What's stopping her from competing against other women are misconstrued beliefs about human anatomy after transitioning. Jonnson is a woman, and hopefully one day people will understand enough about being transgender to allow her to compete with her peers.